Interior illuminator for automobile

Abstract

To provide an interior illuminator for an automobile that prevents light leakage to the driver's seat and light reflection in a window glass, can illuminate a backseat more evenly with an adequate quantity of light, consumes less electric power, generates less heat, has a small size and can be produced at a reduced cost. An interior illuminator has: cold cathode tubes 5, 6; a cold cathode tube driving circuit for driving the cold cathode tubes 5, 6; manipulation switches 12, 13, 14 and 15 for turning on and off the cold cathode tubes; and a housing 2 that houses the cold cathode tube driving circuit and holds the cold cathode tubes and the manipulation switches. The housing 2 is attached in a position on a longitudinal center line of the automobile and behind the driver's seat, and the cold cathode tubes 5, 6 each have an illumination range set to be lower than the lower edge of a window glass behind the driver's seat.

1. An interior illuminator for an automobile that is attached to a ceiling of the automobile, comprising:
 a cold cathode tube having a predetermined length; 
 a cold cathode tube driving circuit for driving the cold cathode tube; 
 a manipulation switch for turning on and off the cold cathode tube; and 
 a housing that houses the cold cathode tube driving circuit and holds the cold cathode tube and the manipulation switch, 
 wherein the housing is attached in a position on a longitudinal center line of the automobile and behind the driver's seat, and 
 the cold cathode tube has a glass tube comprising a first portion of a circumferential perimeter along an entire length of the glass tubes which emits light and a second portion of the circumferential perimeter along an entire length of the glass tubes which does not emit light, 
 wherein light emitted from said first portion of the perimeter of the glass tube emitting light is substantially directed to a lower illumination range than the lower edge of a window glass located behind the driver's seat. 
 
   
   
     2. The interior illuminator for an automobile according to  claim 1 , wherein said housing holds a second cold cathode tube so as to form a pair of cold cathode tubes arranged in parallel and attached to the ceiling of the automobile in such a manner that the cold cathode tubes are placed on the opposite sides of the longitudinal center line of the automobile. 
   
   
     3. The interior illuminator for an automobile according to  claim 2 , wherein said paired cold cathode tubes are provided with primary optical axes thereof being inclined at a predetermined angle oppositely in the lateral direction of the automobile. 
   
   
     4. The interior illuminator for an automobile according to  claim 3 , wherein the primary optical axes of said paired cold cathode tubes are inclined oppositely at an angle of 10° to 20° with respect to a vertical downward direction. 
   
   
     5. The interior illuminator for an automobile according to  claim 1 , wherein said cold cathode tube is supported on a circuit board via a pair of terminal holding sections that cover electrode terminals of the cold cathode tube provided at the longitudinal ends thereof, the circuit board comprising said cold cathode tube driving circuit, and said terminal holding sections are made of an elastic soft material. 
   
   
     6. The interior illuminator for an automobile according to  claim 5 , wherein a surface of said circuit board on which said cold cathode tube is mounted has a highly bright color. 
   
   
     7. The interior illuminator for an automobile according to  claim 1 , wherein said housing has a diffuse-transmission member that at least covers said cold cathode tube and transmits and diffuses the light from the cold cathode tube. 
   
   
     8. The interior illuminator for an automobile according to  claim 1 , wherein the ceiling of said automobile has a curve in profile, and said cold cathode tube is located above a plane connecting upper edges of window glasses and accommodated in the curve of the ceiling. 
   
   
     9. The interior illuminator for an automobile according to  claim 1 , wherein said cold cathode tube has an electrode provided on a side wall of the glass tube, wherein said first portion of the perimeter of the glass tube emitting light is the perimeter of the side wall of the glass tube on which no electrode is provided. 
   
   
     10. An interior illuminator for an automobile that is attached to a ceiling of the automobile, comprising:
 a pair of cold cathode tubes having a predetermined length; 
 a cold cathode tube driving circuit for driving the cold cathode tubes; 
 a manipulation switch for turning on and off the cold cathode tubes; and 
 a housing that houses the cold cathode tube driving circuit and holds the cold cathode tubes and the manipulation switch, 
 wherein the housing is attached in a position on a longitudinal center line of the automobile and behind the driver's seat, and 
 the cold cathode tubes have glass tubes comprising a first portion of a circumferential perimeter along an entire length of the glass tubes which emits light and a second portion of the circumferential perimeter along an entire length of the glass tubes which does not emit light, 
 wherein light emitted from said first portion of the perimeter of the glass tubes emitting light is substantially directed to a lower illumination range than the lower edge of a window glass located behind the driver's seat, 
 wherein said cold cathode tubes are arranged in parallel and are attached to the ceiling of the automobile in such a manner that the cold cathode tubes are placed on the opposite sides of the longitudinal center line of the automobile, and 
 wherein said pair cathode tubes are provided with primary optical axes thereof being inclined at a predetermined angle oppositely in the lateral direction of the automobile. 
 
   
   
     11. The interior illuminator for an automobile according to  claim 10 , wherein said paired cold cathode tubes have an electrode provided on a side wall of the glass tubes, wherein said first portion of the perimeter of the glass tubes emitting light is the perimeter of the side wall of the glass tubes on which no electrode is provided.